This invention relates to a spinning or twisting spindle, comprising a spindle top part which is secured in the axial direction against a lifting-out from a spindle housing by means of a first retaining element which is arranged on an interior wall of a wharve bore and is in a detachable form closure with a second retaining element which is arranged on the upper front end of the spindle housing.
In the case of conventional spindles, which are driven by a tangential belt resting against the wharve, the spindle top part, together with the shaft, can be pulled out of the spindle housing in the upward direction. In order to avoid the unintended lifting-off of the spindle top part, mechanically acting securing arrangements of various types are provided for the fixing of the spindle top part on the spindle housing. One of these securing possibilities consists of providing an elastic ring in the area of the end face of the spindle housing, which elastic ring interacts with a collar on the interior wall of the wharve. Such a securing arrangement is called an internal securing arrangement.
In the case of a spinning or twisting spindle of the above-mentioned type known from the German Patent Document DE-AS 11 49 652, an elastic ring is fixed to the end-face cover of the spindle housing and interacts with a ring groove arranged on the interior wall of the wharve bore. In this case, the elastic ring is accommodated by a groove which is machined into the end-face cover. The end-face cover has an axial lengthening which starts out from the end face of the spindle housing and is bounded by ring shoulders so that the groove accommodating the elastic ring is formed by the lengthening and the two ring shoulders. On the spindle housing, the end-face cover is held by means of a flanged edge which is constructed on it and which reaches around the edge area of the end-face cover. In this are of the spindle housing, an upper bearing of the spindle shaft is arranged which is held in the axial direction by means of the end-face cover. Over a portion of its axial length in the radial direction, the elastic ring has a larger diameter than the sleeve-shaped end-face cover so that in this area a ring disk is formed which projects over the cover. On the interior wall of the wharve or the wharve bore, a collar is constructed which has a smaller diameter than the ring disk formed by the elastic ring. When the spindle top part is moved away from the spindle housing in the axial direction, the collar strikes against the ring disk. It is only under the effect of higher forces that the collar deforms the elastic ring such that the spindle top part can be pulled out of the spindle housing.
It is an object of the invention to provide an arrangement by means of which, particularly also in the case of spindles with a small diameter, a stable axial securing is achieved without any impairment of the safety of the bearing seat.
In order to achieve this object, it is suggested in the case of a spinning or twisting spindle of the initially mentioned type that the second retaining element is fastened to a sleeve which is fastened to the outer circumference of the spindle housing and projecting at its front or top end face.
By means of the arrangement according to the invention, it is achieved that the relative large forces which act upon the second retaining element assigned to the spindle housing do not have to be absorbed by the flange and the wall of the spindle housing which is weakened in this area anyhow. By means of the arrangement of the second retaining element on the sleeve, during the pulling-off of the spindle top part, essentially no forces are exercised on the wall of the spindle housing which is weakened in the area of the flange which may possibly lead to a loosening of the upper bearing ring and to a change of the overall bearing geometry. The sleeve, which is lengthened by way of the spindle housing, in the area in which the fastening of the second retaining element takes place, may be manufactured with a sufficient wall thickness while the width of the gap between the spindle shaft and the spindle housing is not important. As a result, the application of the axial securing arrangement according to the invention is also possible in the case of small spindles. Up to now, an internal securing arrangement has probably not been used for the above-mentioned space reasons.
In an advantageous development of the invention, the first retaining element is designed as a collar constructed on the interior wall of the wharve bore, and the second retaining element is constructed as an elastic ring fixed to the sleeve. In this case, the outside diameter of the elastic ring has a diameter that is larger than the inside diameter of the collar. When the spindle top part is pulled off the spindle housing, the elastic ring is deformed only when effected by a higher force in such a manner that the spindle top part can be moved away in the axial direction out of the spindle housing.
In a further development of the invention, it is provided that the elastic ring is accommodated by a ring groove which is inserted on the outer circumference of the sleeve in an area which, on its ends face, projects beyond the spindle housing. By means of this arrangement of the ring groove, it is achieved that, when the spindle top part is pulled off, the introduction of the force takes place into an area which is separated from the bearing seat of the upper bearing. Thus, when the spindle top part is pulled off, the bearing seat is not impaired. Furthermore, this arrangement permits a secure fixing of the elastic ring because, in this area of the sleeve, the ring groove can be manufactured with a sufficient wall thickness.
In order to permit a simple and cost-effective type of fastening of the sleeve, it may be provided that the sleeve is pressed onto the spindle housing. In addition or as an alternative, it may be provided that the sleeve is form-lockingly connected with the spindle housing. In this case, the spindle housing may have a ring groove which accommodates an assigned collar of the sleeve in a form-locking manner. The sleeve is expediently wedged over in a form-locking manner in the area of the ring groove. As a result, a further cost-effective and secure fastening of the sleeve is permitted.
In a further development of the invention, a ring-shaped gap may be provided in the area of the seat for an upper bearing of a spindle between the spindle housing and the sleeve, the gap being open in the direction of the end face of the spindle housing. Thus, a direct contact is avoided in the area of the bearing seat of the upper bearing. Even in the case of strong outside forces exercised on the internal securing arrangement, no deformation can therefore occur in the area of the upper bearing.
In a further development of the invention, it may be provided that the spindle housing has a collar on which the sleeve rests and which fixes it in the axial direction. A collar of this type which is arranged on the spindle housing mainly secures the sleeve in cases in which the spindle top part is introduced into the spindle housing.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.